中文摘要：

研究了稀土类β晶成核剂（WBG）在不同添加量下，对聚丙烯（PP）力学性能以及热性能的影响。利用差示扫描量热（DSC）和广角X射线衍射（WAXD）等测试方法对其成核效果进行了评价。结果表明，随着成核剂用量的增加，β晶相对含量随之单调增加，体系的冲击强度也随之提高；添加量为0．1％时，β晶相对含量〉90％，诱导生成的β晶PP（β-PP）的冲击强度达到最大值，比纯PP（α-PP）提高了近2倍；当成核剂用量〉0．1％时，虽然体系中β晶相对含量保持稳定值，但热变形温度随着成核剂浓度的增加而持续逐渐增大。同时，经历多次热处理后，β晶的相对含量基本保持不变，显示出该成核剂具有良好的加工稳定性。

英文摘要：

The effect of rare earth β-nucleation （WBG） on mechanical properties and heat-resistance of polypropylene have been investigated. The relative amount of β-form was determined by using differential scanning calorimetry （DSC） and wide-angle X-ray diffraction （WAXD）. With increasing content of the nucleating agent at a range of 0-0.1%, the phase content and the Charpy impact strength dramatically increased. Addition of 0. 1 % induced to present more than 90% of the β-form, the Charpy notch impact strength up to nearly two times higher than that of non-modified polypropylen. With the further increasing the WBG concentrations, the temperature of deflection under load （HDT） monotonously increases, while both the relative content of β-form and the Charpy notch impact strength no longer increased. It was found that after several heat-cooling circles, no obvious changes occurred on the proportion of β-phase peaks in DSC traces, which revealed that the WBG is a kind of stable nucleating agent.